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UNITED STATES PATENT error-:

LOUIS A. BRODE, OF GLASGOW, ASSIGNOR TO CHARLES DOUGLAS &' 00., OF NO. 60 BARRON STREET, PORT DUNDAS, NORTH BRITAIN.

MANUFACTURE OFSLABS 0R BLOCKS FROM WOOD 0R PAPER PULP, FROM SHEETS MADE FROM SUCH PULP, &c.

SPECIFICATION forming part of Letters Patent No. 233,322, dated October 19, 1880. Application filed September 11, 1880. (N 0 specimen.) Patented in England December 17, 1879.

To all whom it may concern Be it known thatI, LoUIs ABRAHAM BRODE, of Glasgow, in t-he county of Lanark, North Britain, have invented Improvements in the Manufacture of Slabs or Blocks from Wood or Paper Pulp or from Sheets Made from such Pulp, the same being applicable for other purposes, for which I have obtained Letters Patent of the United Kingdom of Great Britain and Ireland by my petition, bearing date the 17th day of December, 1879, of which the fol- In carrying my said invention into effect in making flat slabs or blocks, such as table-tops or the like, the pulp is formed into sheets or layers, and deprived of the greater part of the water the pulp contains, so that two, three, or

more such sheets or layers will give the required thickness of slab or blocks or similar articles; or sheetsalready formed-such, for example, as straw boardsmay be employed, in place of the said sheets or layers of pulp, for the purposes of my invention. The said sheets or layers are then coated with a solution of gum tragacanth or tragacanthin, formed by dissolving it in water to about the thickness of treacle. When this solution has thoroughly soaked into the material of the said sheets .or layers the said sheets or layers are coated with a paste formed as follows: A mixture of rye or Wheaten flour, pitch-powder, litharge, alum, and gelatine is prepared by boiling together about thirteen parts, by measure, of the flour with two parts, bymeasure, each of the alum and gelatine and one part, by measure, of the litharge. When this mixture has been boiled and thoroughly incorporated by stirring during boiling, it is allowed to become cold, when about two parts,

by measure, of fine powdered pitch are mixed and thoroughly incorporated therewith.

The sheets or layers, coated as above described, are placed together, such a number of such sheets orlayers beingemployed as is requisite to form the required thickness of slabs or blocks or similar articles, which are then placed between zinc or other sheets or plates to separate the said slabs or blocks or similararticles, the one from the other, and the whole is placed in a press and therein subjected to pressure, any press (such as a hydraulic press) which will give a great pressure being suitable for the purpose. The said slabs or blocks or similar artieles are allowed to remain subjected to this pressure for about twelve hours, when they are removed from the press and the zinc or other plates are removed therefrom, and the said slabs, blocks, or similar articles are placed in a drying-chamber or other drying place and submitted therein, for about twelve hours, to a temperature of about 100 Fahrenheit. The said slabs or blocks or similar articles are or may be then covered with veneer, which may be affixed by a solution of gum tragacanth or tragacanthin and the paste before described, or in the ordinary way, or they may be enam' eled, which may be effected as follows: The slabs, blocks, or other articles, when they are removed from the drying-chamber, are submitted to great pressure in the manner hereinbefore described, but between heated metal plates, and remain subjected to this pressure until the said plates become cold. The degree to which these plates are heated may be any degree such as will not burn or char or otherwise injure the material of the slabs or blocks or similar articles. Thefoundation for the enameling is given by saturating them with tar varnish and submitting them to a high temperature, which will cause the tar varnish to penetrate the slabs, blocks, or like articles.

The pulp may be formed at once of the thickness of the slab or block or similar article required, instead of in separate sheets placed together, in which case the solution of gum tragacanth or tragacanthin and the hcreinbefore-described paste are mixed and thoroughly incorporated with the pulp, which is deprived of any excessive amount of water by pressure or otherwise, in the proportions, by measure, of about one part of gum solution and one part of the paste to three parts of the pulp, and the slabs, blocks, or similar articles thus formed are treated by pressure and heat, as hereinbefore described. In carrying this part of my invention into effect a mold is employed, in which the pulp is placed and pressed to expel the surplus water, and after the gum and paste have been mixed with the pulp in the said mold pressure is again applied, by which moisture is expelled and the materials forced into a compact mass. The mold or part thereof may have perforations therein for the escape of the moisture. I prefer, however, to form the slabs, blocks, or like articles as herein first described.

In making the slabs or blocks or like articles, a layer or layers of wood maybe embedded in or between the sheets or layers of pulp or sheets of paper material, so that by the relative proportions of the wood and pulp or paper material auy required weight of slab, block, or like article may be obtained.

In making molded articles, such as basins, the pulp of wood or paper material (from which the greater amount of water is expelled) is mixed with the gum and paste and molded in a mold of a shape corresponding to that of the article being made, and otherwise treated cs 30 sentially as before described with regard to the making of slabs or blocks or like articles at once of the requisite thickness. The articles thus formed may then be enameled, as before described.

I claim- The improvements in the manufacture of slabs or blocks from the pulp of wood or paperpulp, or from sheets made from such pulp, and in the manufacture of such other articles as 40 can be molded and submitted to pressure from the said materials, by treating the said materials with a solution of gum tragacanth or tragacanthin and a paste, (composed as hereinbefore described,) and subjecting them to heat 4 5 and pressure, essentially as hereiubefore described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

LOUIS A. BRODE. [L. 8.]

Witnesses:

Ronsar ADAM GUNN, JAMES SMITH BEGG,

115 St. Vincent Street, Glasgow. 

